This article is about this case where the passed pawn cannot get promoted without the King’s help (the other King being in the square of the pawn, remember the rule of the square ?).

There are many ways to tackle the endgame King + pawn VS King, but a concept that I find very useful in practice is the notion of **Key Square**.

The definition is the following: “A Key Square is a square such that if a player’s king occupies it, he can force the pawn to promotion, regardless of where the other King is and regardless of which side is to move, and against any defense.”

What we understand from this definition is that you should always try to occupy one of the Key Squares with your King. Now we are going to detail which squares are the Key Squares, depending on where the pawn is located.

## The Rook Pawn

The rook pawn is an exception and we are now looking at all the other pawns. We can define the Key Squares of pawns located on the fifth, sixth or seventh rank.

## The “standard” Pawn

### Pawn on the seventh, sixth or fifth Rank

The Key Squares of a pawn on the sixth rank and on the fifth rank are similar.

To understand why these squares are key squares, you need to understand the concept of opposition.

### Pawns on other Ranks

Pawns located on the second, third or fourth rank have more or less the same Key Squares, as we will see. As in the previous example, the topic here is **what** the Key Squares are, and not **why** the win is forced.

Now let’s test your memory with a few questions.

## Using the Key Squares to play the right Move

Now, I am going to ask you to evaluate more complex positions. The key to answer correctly is to think about the Key Squares.

The key question you have to answer here is “Can I reach one of the Key Squares with my King ?”. This question is easier when we highlight where they are.

As the previous example shows, the Key Squares are here to help you in your calculations: if at one step, the King reaches a Key Square, you can stop there: you know you are winning.

Here is another, more complex example, involving Key Squares and Opposition.

It seems like there is hardly any difference between the two options. Yet, one is winning, and the other one gives only a draw.

We start to understand the problem: the black King is close enough to block the road that goes through c4. Is it the same if the white King goes the other way ?

This endgame and some others are analyzed further in this video about Key Squares.

Even simple endgames sometimes need subtle moves and strategies to win. This is often true in King and pawn endgames that seem simple on paper but can be surprisingly hard to play. Be careful !

At the end of this article your endgame evaluation skills should have improved significantly ! Note that for the last cases, I have not told you yet how to actually win these winning positions.

To play King and pawn endgames flawlessly, you need to master the art of opposition, how to play winning positions, how to defend drawn positions, and how to promote the Rook pawn. Each of this topic is covered in one of my next articles. Stay tuned !